Broaching apparatus and method



Feb. s, 1949.

Filed Deo. 11, 1945 L. B. GREEN BROACHING APPARATUS AND METHOD 3 Sheets-Sheet 1 Feb. 8, 1949. Il B, GREEN I 2,461,320

n BOACHING yAPPARATUS AND METHOD Filed Deo. 11, 1945 3 Sheets-SheetI 2 IN VEN TOR'. 5E 5. Gees/v l ,Q7-TOEN: m5

Feb. 8, 1949. L'. B. GREEN 2,461,320

I l BROACHING APPARATUS AND METHOD Filed Dec. 11, 1943- 3 Sheets-Sheet 3 INVENToR. EE 5 y @PEs/Y Patented Feb. 8, 1949 UNITED STATES A'PATENT OFFICE 1v Claims.

This invention relates vto the machining -or finishing of various 'articles of manufacture and aims to provide a novel method and apparatus for carrying out such machining a rapid and economical man-ner and 'which method and -apparatus are especially applicable to Ythe production of externally toothed articles such -as spur gears and the like.

The method and apparatus herein 'disclosed represent an improvement over the method and apparatus disclosed in my earlier application, Serial No. 484,186, ledfApril 23, 1943 now Patent No. 2,3825628'granted August 14, i945.

Another object of my invention is to provide a novel method and apparatus Jfor external broaching in which compleniental portions `of a gear blank or the like are machined in successive stages so that upon completion of the staged movement such complemental portions will aggregate the entire portion to be machined.

A further object of the invention is to provide a broaching `method and apparatus of this cha-r*- acter in which the blank is guided and centered in a novel manner for the vlai-caching operation.

`Still another object of my invention is to provide a novel method and apparatus for machin*- ing rgear blanks or the like in which alternate portions of the blank are machined in one stage-- with intermediate portions -being u-sed for Vguiding and centering the blank, and a succeeding stage such intermediate portions are machined while the previously machined alternate portions are used for guiding and centering purposes.

Yet another object of this invention -is to lpro-- vide a novel form of die or external breach which can be used to advantage in my improved Vmethod and apparatus.

Other 'objects and Vadvantages of 4the invention will be apparent from the follow-ing description when taken in conjunction with the accompanying sheets of drawings,v wherein:

Fig. l 4is a longitudinal sectional view oa novel form of die or external breach adapted -tobe used in my improved apparatus and method-,the View being taken las indicated by line I==l of Fig. '2.'

Fig. 2 is a transverse sectional View -of such broach taken on line 2--2 of Fig. l.

Fig. 3 is a simi-lar `sec-tional view showing another such lexternal broach Afor use in paired or staged relation with the broach of Figs. 1 and 2.

Fig. 4 is a plan View, with portions in section, showing a breaching machine (n nbodying`- my novel form of external broach and with which my breaching method can be carried out. l

Fig. 5 is a transverse Vsectional view of broach- `i?! ing apparatus of this ki-nd in which of hollow broaches is used.

Fig. `6 is another transverse sectional View showing similar apparatus, .in which 'two v'pairs of hollow breaches are used.

Fig. 7 is a plan view showing -a blank or work piece of a yform which can Pbe economically machined or :Finished by my broachin-g method and apparatus, the blank being 'shown after the first stage of the broaching operation.

Fig. 8 isa detail view showing-on `a larger scale the cooperation of the cutting teeth vwith the blank and Fig. 9 is another .plan view of the blank-showing the same upon completion. of the breaching operation. v Y

As Will be apparent from the following detailed description, my invention is applicable to the machining or nis-hing of a varietyYo-f work pieces a single pair of different sizes and shapes'but vis particular-ly useful in the production of `externally -toothed articles including gears, saws, ratchet wheels vand the like. In Figs, 7 and 8 I show a )spur gear IQ as an example of an article which canV be economically machined or finished by the VuseY novel 'method and shows machining 'or externalr breaching apparatus, of thel kind disclosed in said earlier application, embodying 'a plurality of elongated `hollovv dies or external breaches IIA and I2 in which the machining of the blank Ill is carried out in successive stages as explained in greater detail hereinafter. These broaches are idisposed in adjacentor co-extensive relation with their axes substantially parallel Aand are suitably held in this relation as by being mounted in a frame I3. v

At opposite ends of the broach li and in substantially co-axial alignmenttherewith are fluid cylinders Ill and I5, of which the cylinder I4 is a power cylinder and the cylinder I5 is a cushioning or resistance cylinder. l opposite ends of the broaoh I2 are fluid cylinders I6 and I1 of which the cylinder I 5 is a power cylinder and the cylinder II is a cushioning orY resistance cylinder'. These lpairs'o'f cylinders may be held in this desired ooeaxial alignment with the breaches II Iand I2 by suitable framemembers 18- Pistons I9 are reciproca'bly operable in the cylinders I4 and I5 and -a-re connected yrespe'cti/'e- Similarly, atv

ly with a pair of cooperating chuck members 2l and 22 by means of piston rods 23 and 24 projecting from the adjacent ends oi these cylinders. Pistons 26 are reciprocably operable in the cylinders Ic and I'I and are connected respectively with a pair of cooperating chuck members 28 Vand 29 by means of piston rods 3E! and 3| projectthe blanks I therebetween and push er carry the blanks while being thus clampingly held, through the broaches II and I2. Any suitable motive uid can be used in the chuck actuating cylinders but I prefer to use hydraulic pressure in the power cylinders I4 and IB and either hydraulic or air pressure in the cushioning or resistance cylinders I and I1.

The breaching apparatus and method illustrated in Fig. 4 can embody any desired number of broacheafor example, it can be provided with a single pair of broaches as indicated in Fig. 5 or can be provided with two pairs of broaches as shown in Fig. 6. When one pair of broaches is employed, Vsuch as the broaches II and I2 shown in Fig. 5, the machining of the article I2 is carried out in two successive stages. When two pairs of broaches are employed, such as the pairs of broaches II, IIa and I2, I2a. shown in Fig. 6, the machining of the article is carried out in four successive stages. These staged operations are described in greater detail hereinafter.

The apparatus shown in Fig. 4 also includes feed and transfer dials 34 and 35 located at opposite ends of the hollow breaches and mounted for rotation on a shaft or spindle 35. These dials have appropriate openings 31 therein adapted to receive the blanks I0 and to align the same with respect te the various broaches. The dials 34 and 35 are driven in timed relation to the actuation of the cooperating chuck members as described in greater detail in said earlier application. The driving means for the dials 34 and 35 may include a power device 38, having pinions 35 meshing with gears 43 provided en the dials.

An important part of my improved breaching apparatus and method is the novel construction and manner of using the breaching dies II and I2 and which will now be described in greater detail. As shown in Figs. l to 3 inclusive each of the broaches II and I2 comprises an outer housing er sleeve 42 in which a plurality of lengitudinally extending sections er segments 43 and 44 are mounted in an annular series so as to define a longitudinal passage 45 through which the chuck members 2I and 22 (23 and 24 for the breach I2) and the blank I0 are axially movable. The segments 43 and 44 are transversely curved and arefixedly mounted in the housing 42 by being held in seating engagement with the inner surface 45 thereof by means of the screws 4l. The segments are held against annular shifting in the housing by means of an interfitting engagement with the latter, as indicated at 48, and are held against axial movement by the end plates 49 which are connected with the housing by screws 5G. The broaches II and I2 have their ends in abutting relation with the frame I3 and are mounted in the upright portions I3a and I3b of the latter by means of the aligning or guiding sleeves 5I te which further reference will presently be made. As shown in the drawings a full l'annular series of the segments 43 and 44 is pro- 5 vided in each of the tubular outer bodies iI and I2 so as to denne tubular sleeves therein.

Alternate segments of the annular series, in this instance the segments 43, are provided with cutting teeth 52 and the intermediate segments 1e 44 serve as a guiding and centering means for the chuck members 2l and 22 and the blank It. The

. cutting teeth 52 are arranged in axially extending rows which are spaced circumferentially of the breach to correspond with the recesses er spaces Illa between the pairs of teeth Ib of the blank. 'Ihe cutting teeth 52 are of a shape or contour to produce teeth and recesses of a desired shape en the blank and are of progressively varying height such that the axial movement of the blank through the passage 45 of the breach in 'a direction from right to left as seen in Fig. 1, will result in a progressive shaping of the gear teeth IIlb and deepening of the recesses la. It will be noted in this connection that the radial 251 distance of the tops of the cutting teeth 52 from the axis of the breach II is less at the right hand end than at the left hand end and the difference between these measurements will depend upon the height of the teeth to be eut or generated en alhe blank.

The intermediate segments 44 are plain segments, that is te say they do not have any cutting teeth thereon but are provided with smooth or plain surfaces 53 which serve as guiding and cen- 35` tering surfaces for holding the chuck members and the blank I in properly centered relation during movement through the passage of the breach. The guide surfaces 53 are preferably located a radial distance 54 from the axis of the obroach such that the rim or periphery I tlc of the blank will be in sliding engagement therewith. Usually the rim or periphery Illc of the blank I3 is in a condition such that it is not necessary to machine the tops of the gear teeth during the ii breaching operation and hence, the cutting teeth 52 are usually of a height such that clearance spaces 55 are left between the segments'43 and the tops of the gear teeth IIlb being formed er generated on the blank.

The chuck members 2l and 22 are similar in form and each comprises a body 57 mounted on an extension 56 of the corresponding piston rod. Each chuck member has an annular rim portion or end face 58 which cooperates with a similar 55- portion of the adjacent chuck member for exerting a clamping action on the blank Ill at a point adjacent the rim or periphery of the latter. The engagement of the chuck members with the blank K at this point results in the blank being securely 60 clamped and held adjacent the portions thereof which are acted upon by the cutting teeth 52 of the breach. By holding the blank in this manner all distortion, vibration or chattering of the blank is prevented during the breaching operation and @-1 consequently the formation of the teeth is carried out in a very smooth and accurate manner. The chuck members 2i and 22 are provided with spring-pressed axially movable plungers 59 having tapered ends 59a which engage in the hub opening of the blank Iii and center the latter with respect to the axis of the chuck as the chuck members close into clamping engagement with the blank. As shown in Fig. 2 the outer surfaces of the chuck members 2I and 22 have spaced recesses siderable detail, it will' be understood, of course, that I do not wish to be correspondingly limited but regard my invention as including all changes and modifications coming within the spirit of the invention and the scope of the appended claims.

Having thus described my invention, I claim:

l. The method of breaching which comprises advancing a gear blank or the like through a hollow broach, machining certain portions of the blank during the advance movement and simultaneously using other portions of the .blank for slidably supporting and centering the blank in the hollow broach during the advance movement, and then subjecting the blank to another such advance movement and machining said other portions and simultaneously using the previously machined portions of the blank for slidably supporting and centering the blank in the hollow broach during the second advance movement.

2. The method of breaching which comprises advancing a gear blank or the like through a hollow broach, machining spaced portions of the blank during the advance movement and simultaneously using alternate portions of the blank for slidably supporting and centering the blank in the hollow .broach during the advance movement, and then subjecting the blank to another such a-dvance movement and machining said alternate portions and simultaneously using the Previously machined space portions for slidably supporting and centering the blank in the hollow broach during the second advance movement.

3. The method of broaching which comprises holding a gear blank .by clamping pressure applied to opposite sides and adjacent the periphery thereof, advancing the blank while thus held in a hollow broach and machining alternate portions only'of the periphery of the blank during such advance movement and simultaneously using the portions intermediate said alternate portions for slidably supporting and centering the blank in said broach, and again moving the blank while thus clampingly held through a hollow broach and machining said intermediate portions while using the -previously machined alternate portions for slidably supporting and centering the blank.

4. In apparatus of the character described, a`

tubular outer body, a full annular series of longitudinally extending transversely curved segments disposed in coextending contiguous relation to each other and mounted in said tubular outer body so as to define an inner sleeve therein in which one or more of said segments carrying cutting teeth and one or more of the remaining segments provide a work guiding means.

5, A hollow broach comprising a tubular outer body, a full annular series of longitudinally extending transversely curved segments disposed in coextending contiguous relation to each other and mounted in said tubular outer body so as to define an inner sleeve therein, alternate segments of the series having cutting teeth thereon and the intermediate segments of the series having wor guiding and centering surfaces thereon. i

6. In broaching apparatus, an elongated hollow broach having cutting means therein, a chuck adapted to carry a blank to be machined and being movable axially in said broach for engaging the blank with said cutting means, and cooperating key and keyway elements on the outer perimeter of said chuck and inner perimeter of said broach for aligning the chuck with respect to' the broach during such movement.

7. In broaching apparatus, an elongated hollow broach having annularly spaced longitudinally extending groups of cutting teeth and longitudinally extending guide means between said groups of cutting teeth, a chuck comprising cooperating members adapted to clampingly carry a blank to be machined and being movable Vaxially in said hollow broach with portions of the blank engaging said cutting teeth an-d other portions engaging said guide means, and cooperating key and keyway elements on the outer perimeter of said chuck and the inner perimeter of said broach for aligning the chuck with respect to the broach during such movement, the aligning elements of said broach extending longitudinally thereof and being located on said longitudinally extending guide means.

8. In broaching apparatus, an elongated hollow broach having annularly spaced longitudinally extending groups of cutting teeth and longitudinally extending guide means between said groups of cutting teeth, a chuck comprising cooperating members adapted to clampngly carry a blank to be machined and being movable axially in said hollow broach with portions of the blank engaging said cutting teeth and other portions engaging said guide means, and cooperating key and keyway elements on said chuck and broach and preventing annular shifting therebetween during the breaching operation.

9. In breaching apparatus, an elongated hollow broach having therein annularly spaced longitudinally extending toothed sections and longitudinally extending guide means between one or more pairs of said toothed sections, and a chuck shiftable axially in said broach for moving a blank along said toothed sections in cutting engagement therewith, said chuck having annularly spaced peripheral recesses located to correspond with said toothed sections and having follower means on its periphery between one or more pairs of said peripheral recesses for cooperation with said guide means.

10. In breaching apparatus, an elongated hollow broach having therein annularly spaced longitudinally extending toothed sections and longitudinally extending guide means between each pair of said toothed sections, and a chuck shiftable axially in said broach for moving a blank along said toothed sections in cutting engagement therewith, said chuck having annularly spaced peripheral recesses located to correspond with said toothed sections and having follower means on its periphery between each pair of said recesses for guiding and centering cooperation with said guide means.

11. In broaching apparatus, an elongated hollow breach having therein annularly spaced longitudinally extending toothed sections and longitudinally extending guide means between one or more pairs of said toothed sections, a chuck shiftable axially in said broach for moving a blank along said toothed sections in cutting engagement therewith, said chuck having annularly spaced peripheral recesses located to correspond with said toothed sections and having follower means between one or more pairs of said recesses for cooperation with said guide means, and cooperating key and keyway elements on said guide and follower means for holding the broach and chuck against relative annular shifting.

12. In breaching apparatus, a plurality of hollow broaches each havingiannularly spaced longitudinallyextending groups'ofcutting teeth, the groups of cutting teeth of one broach being annularly oliset with respect to the groups of an other of said breaches, the oiset relation and the width of the tooth groups being such that the tooth groups for the two breaches together aggregate a full breaching periphery for the blank to be breached, means for moving -a blank through said hollow breaches in succession, andV transfer means adapted to receive the blank from said one breach and to align the blank with respect to the succeeding breach.

13. The method of breaching which comprises advancing a gear blank or the like through hollow breaching means, machining spaced portions of the blank during the advance movement and simultaneously using alternate portions of the blank for slidably supporting and centering the same in the hollow breaching means during the advance movement, rotating the blank about its axis, after the rst advance movement, through an angular distance corresponding with the angular spacing of said spaced and alternate por-- tions, and then subjecting the blank to another such advance movement through the hollow breaching means and machining said alternate portions and simultaneously using the previously machined spaced portions for slidably supporting and centering the blank in the hollow breaching means during the second advance movement.

14. A hollow breach comprising a tubular outer body, and a full annular series of longitudinally extending transversely curved segments carrying cutting teeth and disposed in coextending conn tigueus relation to each other, said segments'be ing mounted in said outer body so as to form an inner sleeve therein.

15. In breaching apparatus, an elongated hollow breach having annularly spaced lengtudinally extending groups of cutting teeth and longitudinally extending guide means between said groups of cutting teeth, a chuck comprising co operating members adapted to clampingly hold an annular blank to be machined, said chuck being movable axially in said breach for advancing said blank therein, means on said chuck and engageable with the blank for centering the latter with respect to the chuck, and means on the chuck for sliding engagement with the guide means of the breach for guiding and centering the chuck in the breach.

16. In breaching apparatus, an elongated hollow breach having annularly spaced longitudinally extending groups of cutting teeth and 1ongitudinally extending guide means between said groups of cutting teeth, a chuck comprising cooperating members adapted to clampingly hold Ll O therebetween an annular blank having a, central opening, said chuck being movable axially in said breach for advancing said blank therein, means on said chuck for-sliding engagement with the guide means of the breach for guiding and centering the chuck in the breach, and a plunger movable in said'chuck and having a tapered end engageable in said central opening for centering the blank relative to the chuck.

17. In breaching apparatus, a pair of hollow breaches each having annularly spaced longitudinally extending groups of internal cutting teeth and longitudinally extending internal guide means between said groups` the groups of cutting teeth of one breach being annularly offset with respect to the groups of the other of said breaches and being of a width substantially equal to the width of the intervening spaces of said other breach, a chuck adapted to clampingly carry an annular blank to be machined and being axially movable in one of said breaches for causing alter-y nate portions of the rim of the blank te be machined by the spaced groups of cutting teeth of said one breach, means en said chuck for sliding engagement with the guide means of sai-d one breach for guiding and centering the chuck therein, a second chuck adapted to clampingly carry said annular blank and being axially movable in said other breach for causing the intermediate portions of thev rim of said blank to be machined by the spaced groups of cutting teeth of said other breach, and means on said second chuck for sliding engagement with the guide means of Said other breach for guiding and centering the second chuck therein.

Y LEE B. GREEN.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Da e 772,841 Smith Oct. 18, 1904 1,070,561 Walker Aug. 19, 1913 1,300,092 Acton Apr. 8, 1919 1,318,102 Oakley Oct. 7, 1919 1,429,398 Barth Sept. 19, 1922 1,527,697 Olsson Feb. 24, 1925 1,935,775 Halborg Nov. 21, 1933 2,106,212 Halberg Jan, 25, 1938 2,115,186 Yager Apr. 26, 1938 2,194,595 Hart Mar. 26, 1940 

